改进的原子吸收法测定土壤样品中的6种重金属元素  

Determination of six heavy metal elements in soil samples by improved Atomic Absorption Spectrometry

作　　者：刘香英[1] 袁建[1] 崔建勇[1] 李振涛[1] 刘高辉[1] 张静波[1] LIU Xiangying;YUAN Jian;CUI Jianyong;LI Zhentao;LIU Gaohui;ZHANG Jingbo(Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业北京地质研究院

出　　处：《世界核地质科学》2019年第2期109-115,共7页World Nuclear Geoscience

摘　　要：原子吸收法是常用的测定重金属元素的方法,由于土壤中有机物含量较高,因此在测定土壤样品时,主要的影响因素有消解方法、消解仪器、消解体系、消解温度、加酸顺序、测定时掩蔽干扰元素的方法以及仪器的测量条件。在研究上述影响因素后认为,选择电热板作为消解土壤样品的仪器;选择HCl-HNO3-HF-HClO4全量分解的方法;控制消解温度为140℃;溶解样品时先赶尽HCl,最后加入HClO4以进一步分解样品中的有机物并避免盐酸与高氯酸同时存在而导致的铬元素分析结果偏低;选用氯化铵作为掩蔽剂,以掩蔽铁、铝、钙和镁等共存离子的干扰,使样品前处理简便快速,且一次溶样可依次测定铜、锌、铬、铅、镉和镍6种元素,提高了工作效率,节约分析成本。此外,测定结果的灵敏度受仪器的测量条件的影响很大,应根据样品溶液的浓度范围选择适合的波长,根据各元素的特殊性质选择狭缝的宽度,火焰类型等,以提高测量的灵敏度。对国家一级标准物质的分析测试,取得了满意的结果。分析方法精密度Cu、Zn、Cr、Pb、Cd和Ni分别为3.39%、1.52%、1.77%、2.26%、4.08%和4.00%;检出限分别为3μg·g-1、3μg·g-1、5μg·g-1、2μg·g-1、0.1μg·g-1和0.5μg·g-1。This paper discussed the effect of different dissolving instruments, dissolving system,dissolving temperature and acid adding method on soil sample deterring results, as well as the methods of masking the interference elements. The decomposition method of HCl-HNO3-HF-HClO4 was achieved with the company of electrothermal plate, which was used to dissociate and control the temperature at 140 ℃ while the soil samples were dissolved. In order to avoid HCl and HClO4 residual, the HCl was added in the first place, followed by HClO4·NH4Cl was used to avoid the interference of Fe, Al, Ca, Mg and other coexistence ion and accelerate the pretreatment process. By using this method, Cu, Zn, Cr, Pb, Cd and Ni could also be analyzed in sequence in a single dissolution, which significantly improved the working efficiency and saved the cost of analysis. In addition, the conditions of the instrument also have a great impact on the sensitivity of the result,which could be improved by selecting the proper wavelength according to the range of the sample, the width of slit and the type of flame. By analyzing national standards material GBW07401, the standard deviation of Cu, Zn, Cr, Pb, Cd and Ni was found to be 3.39%, 1.52%, 1.77%, 2.26%, 4.08%,1.00% respectively and the detection limits to be 3 μg·g-1, 3 μg·g-1, 5 μg·g-1, 2 μg·g-1, 0.1 μg·g-1,0.5 μg·g-1 correspondently.

关 键 词：土壤 重金属元素 影响因素 原子吸收法 

分 类 号：X131.3[环境科学与工程—环境科学] O657.3[理学—分析化学]